PeterW

Blackening some new eyepiece tubes and had some spare.... looks like yoda has joined the dark side 😉 (under bright light with camera exposure stretched.. it’s not brown!) Peter

We need to dig into the past climate reanalysed... so we can have some values to pop in.... let me have a look, see what might be available. What time span have you data for Magnus? Peter

There are forecast for water vapour content and also aerosol forecast, but getting hard numbers to correlate to SQM data could be tricky.... but the data should exist. Peter

Depends on the coating material and whether it’s been AR coated, like celestron, Orion and others can add to improve the result. If you treat coating a with care then they should last for ages, they are typically oxide overcoated that stops them being corroded. Reflectors typically have fewer, but lossier interfaces compared to refractors. 656nm is close enough to visible that broadband coati NV a should still work fine. Aluminium coating S have a bit of a drop around 800, so maybe we should ask for protected silver mirrors instead? https://www.edmundoptics.co.uk/knowledge-center/application-notes/optics/metallic-mirror-coatings/ No info on them different “coated mirrors” that companies have, which could reduce this somewhat. Peter

I have plenty of gloves that don’t work (previous post), so might as well make some do something useful. I have NO plans to add thread to my new ultrawarm BlackDiamond mittens. Peter

What is the R^2 of your regression? Interesting stuff. I’ve seen notes about the variation due to different effects like the milkyway. Be interesting to see your time series data. Peter

Probably been covered before, but I got some generic conductive thread online and stitched some through the tips of my main two smartphone screen using fingers on my right hand. The thread provides an electrical connection between you and the screen so you dont need to take your gloves off to use your device! I gave it a go with a pair of glove liners I had lying about and bingo it works nicely. So I can keep the worst of the cold off my fingers and still use skysafari. peter

Watch yet self that disk looks bitey! Peter

Depends on the mirro coating, can go >95%, easier to get bigger and faster... lots of options. Peter

Our club dark site is a little over 21, but as you say, transparency is key. >21.5 in the U.K. will be pretty rare. LED depending on colour warmth can be erroneously measured with satellites and SQM. It’s sad the people have started over using LED, an opportunity missed to make things cheaper and better for everyone L When you have binoculars your filter collection can start to breed like rabbits! I am enjoying my tripod mounted angled 70mm and waiting to see what dark skies will let it deliver with them. Fully stable two eyed views make the faint stars pop into view, aperture just changes image scale for a constant exit pupil. There seems a recognition that binoculars can hold their own against “the big stuff” (dobs), picking up some pretty dim nebulae. Smaller kit certainly is easier to fit in a flat, but the costs of two eyed views certainly do not scale linearly! PEter

Hmmm... the 9x50 version unscrews nicely with finger tips.... the 50mm guider version won’t shift even with bits of rubber wrapped round the tube to help grip. Might even have gently used whacked it too. Right I’ll put the kettle in... to heat the end... a cup of tea will follow, especially if nothing moves! Peter

Need to eat some spinach (popeye style) and have another go... thanks peter

Any idea how the back part of the typical 9c50 finder scope is held in... ?? I have one and a “50mm guide scope” that is the same with an open back. I was to repurpose these, but I need to remove the back section. Tried to unscrew... nothing budged, could be glued? I’d prefer not to get a saw out in case I want to return them to their original form. Ideas?? Peter

Great report, shows that aperture isn’t everything for these nebulae!. Many of those nebulae you’re after are of the galactic hydrogen variety so a hydrogen beta filter would be the way to go. Trust the SQM, those online maps look nice but have not been locally calibrated. You’ll find nights vary a bit, practice checking the Bortle descriptions to narrow things down, seeing you’re lucky to have dark skies not too far away. Peter

One chap I the US has done so, but with a 67mm plossl and an f4 imaging newtonian you can get down to around f1.6, which should be fast enough (maybe not for @GavStar though)! An explore scientific coma corrector can avoid loss of speed if you wanted. peter

My friend needed to get his EMS slightly customised, very fast and professional response and turnaround from Mr Matsumoto. Be interesting to hear how your adventure continues... peter

The Exit pupil is just the aperture/mag so your quantum’s are 5 or 2.5mm http://www.aokswiss.ch are the Swiss bino makers. I’ve looked through a friends EMS, very nice and easy to use and merge between users, didn’t think they were that costly? 120mm bins very popular, there is a “bargain” semi apo version. http://www.deep-sky.co.uk/telescopemaking.htm have made several sheet metal binoculars over the years. The late Bruce sayre had some plans for a very nice single arm system. PEter drew has made loads in the past, but no plans for new ones as I understand. Noctutec seem to do one of you ask, details here https://www.noctutec.com/astronomie-shop/teleskope-noctutec/someone on cloudynights has one. The web probably has more homebrew ones, so get out the welding rig and plywood….. good luck. Cheers Peter

Two eyes is a bad place to go…. Costs rise rather faster and availability drops with aperture. You’d need to fix the two optical systems very securely and then fiddle some way to adjust the IPD…. there are some good designs and plans online, but you’d be beating quite a rarely trodden path. I was cruising around northern Cygnus with my 70mm APM, pleasant even with the bad light pollution, need to get them under better skies…. the old aperture fever keeps suggesting that bigger bins would be better… How did you get on with the actual large binoculars, be interesting to compare views with similar exit pupils (just an image scale difference). At least these are available upto 120ish mm, beyond that you are on your own! Peter

Cheap monopod and trigger head and a relaxing garden chair can do quite a bit too, take the weight quite well. https://binocularsky.com/binoc_mount.php peter

The differences from coating will be small, the exit pupil difference will likely be much larger. Try them out and return the one you prefer the least. I have the 10x50 and they’re really nice and wide and sharp, though I do use a monopod to stabilise the views. Peter

Needed doing, if your eye is too close the field edges shrink and go all fuzzy. I am sure when I need glasses I will welcome the extra eye relief.... but not yet. Just need to print t meh other spacer now I know the thickness I needed. Peter

As I (currently) don’t need glasses when observing sometimes eyepieces with long eye relief are hard to use, trying to hover my eye in the right place. Suffered from this with some cheap 40mm plossl I got for an experiment. So I’ve added some 15mm extensions (and my bike inner tube patent winged eyecups) so I can use them far more easily and block straylight nicely. Peter

Was wondering, but if the government could fix light pollution then think of all the petrol miles (CO2) that could be saved by the army of amateur astronomers who currently travel miles for dark skies..... Peter

Yes, not wearing glasses I might have to hang in from of them. These are for the APM70. Might get some shorter ones for lunar/solar duty. Time to make some inner-tube winged eyecups. Peter

@Highburymark great minds think (almost) alike. Looking for bigger exit pupils (whilst accepting a much smaller AFOV than I usually accept). Peter